From: Colyn Case at earthlink <colyncase@earthlink.net>
Subject: [LML] Re: Airspeed sensing switch /Auto gear extension / Engine out gear down Issue!
To: lml@lancaironline.net
Date: Monday, January 25, 2010, 7:42 PM

Randy, I need to understand your point more thoroughly.

I think just about every landing in my IVP I have the power all the way back, gear down, flaps full before the flare.

 

It sounds like you are saying that the difference between idle power and no power is so much drag that you can't get the nose up before you are out of airspeed.   I guess I don't see how holding off on gear extension is really going to change what happens in those last few seconds.

 

I do see (and have tested) how rocklike the glide is with everything down and dirty.

 

Colyn

----- Original Message -----

From: randy snarr

To: lml@lancaironline.net

Sent: Saturday, January 23, 2010 3:20 PM

Subject: [LML] Airspeed sensing switch /Auto gear extension / Engine out gear down Issue!

Terrence, Mine is the same as yours only no auto gear down. Only a warning light and horn for low speed and gear up. I would seriously consider changing your set up for the following reason. This is a bit of a long winded response but it brings up a vitally important point for the group.  Gear and flaps down too early with a dead engine will have disasterous consequences every time. With loss of power, gear and flaps should stay up keeping speed above 120 kts IAS until the last seconds before landing. My gear down is a count to 7. Everyone should know how many seconds it takes to get it down and locked as you will only have one shot to get it right in an emergency. You wont' be able to do that with your gear set up. Many Lancair drivers (myself included until recently) have no idea that these how bad these airplanes glide dragging the gear with a windmilling propeller. That is a deadly mistake. Dragging gear and flaps, you need a steep nose down attitude to keep the airspeed at a safe speed. Unfortunately, in that regime you can not flair the airplane. When you try to flair without a little power these airplanes just slow down and hit the ground. The situation is much worse if you are heavy. This is very important for every Lancair driver to understand, With a dead engine if the gear and flaps are down too early (anything sooner than 10 seconds before ground contact) the incident will most likely have a tragic outcome. This is absolutely true. I don't mean to preach but I believe we would still have some good friends with us if we all understood this better. We recently had a fatal crash at my field where an experienced instructor died in a 210 in a similar circumstance which got me thinking about this. The ONLY way to get down safely on your wheels in our airplanes is to keep and extra 15 or 20 KTS of energy (over a typical approach) all the way to ground effect and then drop the gear and flaps and bleed off speed and touch down. That extra energy is used quickly extending the wheels and you will need to be touching down when it is gone or you are toast. This applies to me as much as anyone else.. Randy Snarr N694RS --- On Fri, 1/22/10, Terrence O'Neill <troneill@charter.net> wrote: From: Terrence O'Neill <troneill@charter.net> Subject: [LML] Re: Airspeed sensing switch needed To: lml@lancaironline.net Date: Friday, January 22, 2010, 3:08 PM Thanks for the info, Randy. I have my airspeed sensing switch set a 90 knots, in the gear-up circuit, so that no matter where the gear switch is, it can't raise the gear unless the airspeed is greater than 90 knots. Same on landing.  I fi forget to put the gear switch to down, the gear will come down anyway at 90 knots. The only downside (no pun intended) is that should I want to make a gear-su forced landing, I couldn't... and have considered adding a bypass into the circuit. Any thoughts on that/ Terrence  L235/320 N211AL To: lml@lancaironline.net Date: Thu, 21 Jan 2010 16:53:05 -0500 From: randylsnarr@yahoo.com Subject: [LML] Re: Airspeed sensing switch needed Terrence, I have two sensing switches in my airplane. One used as a gear up warning for landing like is being discussed, the other is exactly what you described. Both are plumbed into the pitot static system and are adjustable with a screwdriver under the pilot side panel. The squat switch opens the gear up circuit under 70 kts. I test it often on take off- I rotate and go gear up while the AS is low and the gear wont  come up, when the AS hits 80 or so up they come. I don't think these should be flying without a gear up squat switch of some kind. I am embarrased to admit I have already inadvertently tested mine. Testing the gear on stands and used the dump valve to drop the gear and left the switch up. Started the plane a few days later and notice the switch in the up position while sitting idling on the ramp. I almost fainted... dropped the switch and closed the dump valve and then sat and thought about it........Glad I had one installed. My friend Dick Mitchel was not so lucky. He raised the gear in front of the hanger and dropped the plane on the ground while it was running. It is way too easy to do. I certified crowd has that point right... Both cost me nothing as my neighbor is in the appliance business. He had a shoe box filled with those and he gave me 2. They are a few ounces of prevention against stupidity of which most of us on rare occasions are afflicted by... Randy Snarr N694RS 235/320 --- On Mon, 1/18/10, Terrence O'Neill <troneill@charter.net> wrote: From: Terrence O'Neill <troneill@charter.net> Subject: [LML] Re: Airspeed sensing switch needed To: lml@lancaironline.net Date: Monday, January 18, 2010, 6:43 AM Bill, Lurking because I share this interest. What are the pros and cons of a simple airspeed sensing switch that just interrupts the gear-up switch circuit until a selected airspeed ... i.e. about 90 knots? Terrence L235/320 N211AL On Jan 16, 2010, at 7:28 AM, Bill Kennedy wrote: I'm going to build the gear not down warning system suggested by Randy Stuart in an earlier email. I thought Aircraft Spruce had a airspeed sensing switch, but I couldn't find it in their catalog. Can any of you help me find a source for the pressure switch? I've never had a close call with the gear in three plus thousand hours of retractable time, but I've always been a little uneasy with no warning system in my LNC2. I had hoped that I could talk Blue Mountain Avionics into building a warning system into their EFIS, but that didn't work out. Randy's system looks great to me and I'm eager to try it. I've attached Randy's drawing just in case others might want to revisit the idea. Thanks -- Bill Kennedy <Gear Warning 1.JPG>-- For archives and unsub http://mail.lancaironline.net:81/lists/lml/List.html